Field
Embodiments of the present invention relate to a method and apparatus for forming composite material to a complex-contoured surface of a forming tool.
Related Art
Composite parts are generally strong and light weight, making them particularly useful in the manufacture of aircrafts. It is known in a variety of industries to form composite parts by applying pressure and heat to an uncured composite material. One method of shaping and hardening composite material into a composite part is called hot drape forming, which is a process that uses heat and vacuum to shape and cure an uncured composite material.
Specifically, hot drape forming can involve placing a vacuum bag over the composite material and sealing the vacuum bag to male tooling. The male tooling can comprise a surface having a number of contours and may include a protruded portion extending outward therefrom. Heat can be applied to the composite material to make it pliable and air is removed from between the vacuum bag and the male tooling so that the vacuum bag compresses the composite material against the male tooling, and the composite material is cured or otherwise hardened into the final composite part.
Another way to form composite parts may include both the male tooling and a matching female tooling or mold. The female tooling has a cavity formed therein with a size and shape corresponding to the protruded portion or contours of the forming tool. Uncured composite material is placed between the male and female tooling, which is then pressed together, and the composite material is cured or otherwise hardened into the final composite part. Heat can be applied during the forming process to make the composite material more conformable.
The matching male and female dies are costly to make and are not usable for any other parts having different sizes or configurations. Furthermore, the male and female die method described above is prone to inducing fiber distortion and/or wrinkling in the composite material, particularly when pressing the composite material into complex contours. The hot drape forming method is primarily limited to forming parts on tools containing convex surfaces. This method is not capable of forming parts on tools containing tight concave surfaces. Fiber distortion and wrinkles in the composite material are detrimental to the quality of the finished composite part.
Accordingly, there is a need for a method and apparatus for forming a composite part that overcomes the limitations of the prior art.